Subchorionic hematoma is known as a leading cause of preterm delivery and miscarriage. Although diagnostic imaging based on ultrasonic tomography is currently performed for subchorionic hematoma, no hematological diagnosis or treatment method has been established yet. Thus, once subchorionic hematoma occurs and progresses, preterm delivery and miscarriage cannot be avoided.
Plasminogen activator inhibitor-1 (PAI-1) is a member of the serine protease inhibitor (SERPIN) superfamily and is the primary physiological regulator of urokinase type plasminogen activator and tissue type plasminogen activator. Although a number of studies have indicated that elevated levels of PAI-1 are associated with several pathological states such as arterial thrombotic events (Non Patent Literature 1) and poor prognosis in cancer patients (Non Patent Literature 2), our knowledge of the consequences of PAI-1 deficiency is still limited due to the rarity of this condition. The present inventors have recently reported a case of genetically identified complete PAI-1 deficiency in a human (Non Patent Literature 3). The patient showed a tendency for massive bleeding, which was also observed in a PAI-1-deficient patient in the previous report (Non Patent Literature 4).
Genetic alterations that lead to a predisposition for bleeding are associated with clinical complications during pregnancy. The most vivid example of this association is congenital afibrinogenemia and congenital coagulation factor XIII (FXIII) deficiency, which result in genital bleeding and spontaneous miscarriage in the first 6 to 8 weeks of gestation if left untreated (Non Patent Literatures 5 and 6).